The purpose of this study is to assess the safety and reactogenicity of a booster dose of diphtheria-tetanus-whole cell pertussis-hepatitis B virus/Haemophilus influenzae type b vaccine (DTPw-HBV/Hib) at 15-18 m and to assess the immunogenicity, safety, and reactogenicity of a dose of Mencevax™ Group A, C and W135 polysaccharide meningococcal vaccine (ACW) at 24 to 30 m in primed subjects.